The marine biome is
(A) the largest biome
(B) has fluctuating temperatures
(C) provides most of the earths oxygen
(D) has a high nutrient concentration
(A) and (C) are correct. The marine biome is the largest biome and provides most of the earths oxygen. It has the most stable temperatures, and it has a very low nutrient concentration because sunlight doesnt reach most of the ocean waters, so (B) and (D) are incorrect.